I think the SASL authentification does not work.
I attach the main.cf, master.cf and the output of saslfinger. I hope somebody is able to give me a hind or a solution.
If I try to send emails with a valid account I get this message:
554 5.7.1 Relay access denied
Thanks

I have setup mail server using this tutorial "Virtual Users And Domains With Postfix, Courier, MySQL And SquirrelMail (Ubuntu 9.10)" but when I set SMTP server in e-mail client to use secure authentication I got "Login to server zm.gotdns.com failed." with those in /var/mail/mail.log :